无致病力青枯雷尔氏菌对烟草根系土壤微生物脂肪酸生态学特性的影响

Effect of the avirulent strain of Ralstonia solanacearum on the ecological characteristics of microorganism fatty acids in the rhizosphere of tobacco

为了探讨无致病力青枯雷尔氏菌对烟草根系土壤微生物群落结构的影响,测定了接种无致病力青枯雷尔氏菌RS-1403和清水对照的烟草根系土壤的磷脂脂肪酸(Phospholipid Fatty Acids,PLFAs),比较分析两种处理下的烟草根系土壤微生物PLFAs组成、含量、微生物群落结构及多样性的差异,以期从微生物群落水平解析RS-1403菌株胁迫对烟草青枯病的免疫抗病机制。结果表明,与对照相比,RS-1403菌株胁迫下烟草根系土壤微生物PLFAs的组成及含量发生了变化,分为5种变化类型,分别为下降型、无变化型、增加50%以下类型、增加50%—100%类型,增加100%以上类型,其中指示放线菌的10Me16∶0含量降低,为下降型,增加100%以上类型的PLFAs均指示革兰氏阴性菌。进一步分析表明,接种RS-1403菌株能改变烟草根系土壤微生物群落结构,促进细菌和真菌的生长,抑制放线菌的生长。接种RS-1403菌株能提高烟草根系土壤的群落优势度Simpson指数、群落丰富度Shannon指数和均匀度Pielou指数,增加土壤的微生物群落多样性。对RS-1403菌株胁迫下烟草根系土壤微生物亚群落分化的比较分析,显示RS-1403菌株处理组与对照组亚群落分化不同,当兰氏距离为2.56时,可将处理组和对照组均分为4个亚群落,但它们的各亚群落组成及特征不同。聚类分析表明,基本上可将取样期内的RS-1403菌株胁迫处理和清水对照的烟草根系土壤分别聚在两个不同的类群中,说明RS-1403菌株能明显改变烟草根系土壤微生物群落结构。

The present paper dealt with the effect of the avirulent strain RS-1403 of Ralstonia solanacearum on the ecological characteristics of microorganism fatty acids in the rhizosphere of tobacco.The tobacco plants were treated with the avirulent strain RS-1403 in the concentration of 1.0×106 cfu/mL with water as control in the semi experiments.The rhizosphere soil was sampled at different days etc.5d,10d,15d,20d and 25d after treatment.The phospholipid fatty acids（PLFAs） of the soil samples were detected by.GC of Agilent6890N.Pattern,content and structure of the microbial PLFAs in tobacco rhizosphere soil were evaluated and the difference between treatment and water control were compared to analyze the immune disease-resistant mechanism of the strain RS-1403 against tobacco bacterial wilt disease at the microbial community level.The results showed that the microbial PLFAs pattern and content in the tobacco rhizosphere soil were changed under the stress of the avirulent strain RS-1403.The fluctuation of microbial PLFAs could be divided five types,e.g.declining type,unchanging type,100% increasing type.Among which,the reduction of 10Me16 ∶0 indicative to actinomycetes represented the decreasing type,all of the PLFAs in 〉100% increasing type indicated to G-bacteria.The statistical analysis showed that the inoculation of RS-1403 could change the microbial community structure in the tobacco rhizosphere soil due to improving the growth of bacteria and fungi and inhibiting the reproduction of actinomycetes.Inoculation of the stain RS-1403 could increase the microbial community diversity in the soil,in which,the enhancement of SHANNON index of community dominance,Simpson index of community abundance and Pielou index of uniformity was revealed.The differentiation of microbial sub-community in the tobacco rhizosphere soil under the stress of the strain RS-1403 was also evaluated with cluster analysis.The results displayed the significant difference existed between RS-1403 treatment and water control.The rhizosphere soil microbe both in treatment and control could be divided into four sub-communities at 2.56 Lance-distance,which were different in the constitutes and characters of PLFAs.The tobacco rhizosphere soils in the RS-1403 threatening treatment and water control could be mainly clustered in to two different groups by using cluster analysis,it was clear that the RS-1403 could alter remarkably microbial community structure in the rhizosphere soil of tobacco.